[llvm] [cmake] Allow multiple LibEdit_LIBRARIES (PR #93896)

[Daniel Thornburgh via llvm-commits]

mysterymath wrote:

`LibEdit_LIBRARIES` is a cache variable, so it's legitimate for a user to specify it explicitly. I do think ideally there would be a way to avoid the manual work we needed to compute that, perhaps using pkg-config. But IIRC, `find_library` wasn't itself aware of the dependencies of a statically-linked `libedit`.

https://github.com/llvm/llvm-project/pull/93896